Highway safety regulations generally limit the 10 length of trailers to 75'. Most large conveyors unfold to 100 or 120' in length. Generally they have two top folds, one at each end of the conveyor. To maximize maneuverability the conventional trailer conveyor is supported by a singular wheeled support. For safe towing and stable operation the conventional trailer must be supported just behind its longitudinal center of gravity. The upper and lower portions of the conveyor, of generally equal length and weight, are hinged to the end portions of the trailer so that the center of gravity does not shift along the length of the conveyor when the conveyor is unfolded from a towing position to the operative position.
U.S. Pat. No. 4,135,614 issued to L. F. Penterman is for an improvement on this conventional trailer conveyor. The improvement comprises a wheeled support which allows for both longitudinal motion and lateral movement of the conveyor in an arc about its material loading point. This allows more material to be stockpiled without moving the conveyor.
Canadian Patent No. 1,057,224 issued to T. J. Johannsen is for a large side folded trailer conveyor. The trailer has a singular wheeled support under its rear central portion. However, unlike the conventional trailer in which the upper and lower end portions swing upwardly, in this trailer the two end portions swing laterally outward, and then into position. The need for two unfolding actuating mechanisms is eliminated. However, two folded sections, and two hinges are employed. The hinges are expensive to manufacture, structurally weak, and a source of operating problems. And as with Penterman's trailer the amount of material which can be stockpiled without moving the trailer, is limited by the stockpiled material approaching the wheeled support of the trailer on the ground. What is needed is not a longer conveyor, but a conveyor having a greater longitudinal extension cantilevered above its point of wheeled support on the ground.